This proposal aims to complete a prospective study of life stress in pregnancy, an issue that has long been a concern of obstetric practitioners. The sample comprises cohorts of 500 prenatal patients assembled in each of two closely comparable areas, who are followed to six weeks postpartum. The independent variables fall into two broad exposure classes: acute individual life stressors and chronic community stressors, both measured at several points in pregnancy. The dependent variables are specific adverse outcomes for mother and offspring selected on the basis of biologic plausibility. A unique feature of the study is the use of biological markers (principally urinary catecholamine levels) to measure both physiologic response to stress and possible intervening pathways from stressors to reproductive outcome. Social support, coping and locus of control are assessed as potential moderating variables. A range of experiences known to affect pregnancy outcome - including behaviors that may be influenced by stress (e.g., smoking, drinking) - are measured as potential confounding or effect-modifying variables. Tests of the effects of acute individual stress relate to reported life events. Tests of the effects of chronic community stress depend partly on subject reports of perceived threat and partly on the comparison of two sociodemographically similar areas: one proximate to a nuclear plant (Three Mile Island); the other not; and both equally exposed to perceived threats from other environmental hazards such as radon. The study is well-launched, with all procedures fully operational. Continuity depends on timely supplemental funding.